Recorder.



C. W. BERRY.

RECORDER.

APPLICATION FILED MAB.. 5, 1910. 1,093,244.

Patented Apr. 14, 1914.

1o SHEETS-SHEET 1'.

In I l Fia@ c. W. BERRY;

RECORDER.

APPLICATION FILED MAB.. 5. 1910. l 0,973,244, Patented Apr.14, 1914.

10 SHEETS-SHEET 2.

with/eases liv/vento a" Uharle Zllerg m? A mffj by m7 f/ff any@ C. W. BERRY.

RECORDER.

APPLICATION FILED Mums, 1910.

10 SHEETS'SHEET 3,

1,093,244. Patented Apr.14,1914.

MM M

att :ya

C. W. BERRY.

RECORDER.

APPLxcATIoN FILED MAR.5,1910.

Patented Apr. 14, 1914.

l() SHEETS-SHEET 4 C. W. BERRY.

RECORDER.

APPLICATION FILED MAR.5, 1910.

Patented Apr. 14, 1914.

10 SHEETS-SHEET 5.

my a. .w r www n u I@ w@ a@ EMM jw C. W. BERRY.V

RECORDER.

APPLICATION FILED MAR.5,1910.

Patented Apr. 14, 1914.

10 SHEETS-SHEET '1.

i D, Jilin/asses llv entor @harias w Ber "ZI M att e C. W. BERRY.

RECORDER.

APPLICATION FILED MAILS, 1910.

Patented Apr. 14, 1914.

Io SHBETSHEET s.

MQ 1 l Inventor v httfys. l

Marle@ bv M md Mag nza wit C. W. BERRY.

RECORDER.

APPLICATION HLED MAB.5,1910.

1,09 3,244. Patented Apr.14,1914.

10 SHEETS-SHEET 8.

Fig. zo:

ltnese Invevzto J emule@ zarr JK by 7 K C. W. BERRY.

RECORDER.

APPLICATION FILED MM45, 1910.

Patented Apr. 14, 1914.

10 SHEETS-SHEET 9.

Ivvve/vvtow:t Charles IILBerry attys.

with eases MQW 'wm.

C. W. BERRY.

RECORDER.

APPLICATION rILED MAR.s,191o.

1,093,244. Patented Apr. 14, 1914.

10 SHEETSSHEET 10.

l' CHARLES W. BERRY, OF WEST SOMERVILLE, MASSACHUSETTS.

RECORDER.

Specification of Letters Patent.

Patented Apr. 14; 1914-.

Application filed March 5, 1910. Serial No. 5747,41?.

T o all who/nit may concern:

known that l, CiiAixLiis W. BERRY, a

, pcitiaeiifofthe United States, and a resident ofgQWest Somerville,- county of Middlesex, Stateof -l\'lassachusetts, have invented an Iiiproyement in Recorders, of .which the follqiviiiggdeseription, in connection with the Eicegilnpanying drawings, is a specification,

pirt etters on the drawings representing like ,-)flhisinvention relates to inethodsof and apparatus for producing displacements propqrlioiialffto the variations of one or more v properties-of a gas which are derived from 15 motions .-or,".displacements proportional to variations in lother properties of the gas.

Thepherein described embodiment of the` -inyeiitiondeals with the production of dis placements proportional to the variations in 20 theiour properties pressure, volume, teinperaturefand entropy of va gas by the utilization fof; displacements proportional to two alofr'tlgie-se four as the primary displacements fomfwhich the remainingtwo are produced. Invirtue ofthermodynamic relations as fgllpwsz- I- it is possible to express any one of the abovenaniedfour properties as a function of any two of the remainingr three properties. This provides a means for delineating the teniperatureV relations of a gaseous body, re

ferred to its variations in volume, pressure or xentropy, or the entropy variations referred to volume or pressure', or other` similar relations. This may accomplished either by a; direct recording apparatus or by f a-projeeting or tracing apparatus, the latter adapted to reproduce from one curve, representing certain physical changes, another curve r'epresenting.,r other physical changes. For example, from -the ordinary indicator 'Y card diagram` showing"pressure-volume variationsof'a gas,l a curve showing either temperatuievolurne, temperatui'epressure, pressuremntropy, volume-entropy, or teniperaiure;entropy variations Imay be directl)y ilraccdpor'sueh a cui-ve'in'lanianncr similarV lo the usual indicator diagram, may be produced directly by a suitable recordiiig apparatus governed by the volume and pressure changes of the gas itself.

Through the use of my invention an indicator card may be secured from ages engine, or other motor or compressor untilizing a medium which follows approximately -the llaws of a perfect gas, showing the temperature-pressure, temperature-volume, pressure-entropy, volume-entropy or temperature-entropy variations of the gas during the engine cycle. This vaffords opportunity for studyingA the ,direction and magnitude of the heat interhanges between the gas andthe walls of the engine, motor or compresser cylinder and for securing other further information .which heretofore 'has been obtainable only through indirect calculation from thecards of the ordinary"I pres surefvoluine indicator. 1

lith the increasing refinement which has laken place in engine design and the use of more highly perfected materials and Workinanship, investigation of the cylinder heat losses and heat changes has become of great importance. To show the nature and inagnitude of the heat interchanges, temperature-entropy diagrams have heretofore been plotted from the pressure-volume diagram by calculating the temperature and entropy of a Isufliciently large number of points to produce a reasonably accurate curve or have been constructed by complicated graphical methods. This, however, requires the eX- penditure of so much labor and time that the production of such a curve constitutes a mathematical feat rather than a practical aid to engine study and design. Notwithstanding the great value to the designer or engineer of the results obtainable from a temperature-entro py diagram, t'he labor is so excessive and the. principles involved so obscure except tothose trained in thermodynamics that the specialist uses such heat diagrams but seldom and the ordinary en- Ygineer scarcely at all.

ployed in securing the ordinary pressurevolume indicator card. The magnitude and character of the heat changes can thereby Figs. l and 6.

`ticula rly pointed he easily ascertained and a betterment of the ruiming conditions of the engine secured by minimizing its heat losses.

The mechanical construction oi recording devices having the purposes stated may be widely varied to secure the desired relative niovements between the recorder and the recording surface. and my invention is susceptible of embodiment in a great varietv of form.h

I have hereinafter described for illustrative purposes several forms of the invention from which, in connection with the accompanying drawings, my invention wiil be bestVV understood, while its scope will be more parout in the 'moended claims.

In the drawings: Figure 1 shows a projecting apparatus for delineating the temperature-volume variations of a gas. Fig. Qshows an indicator for automatically recording temperature volume variations. Fig. 3 is a sectional end elevation partly broken away on the line 3-3 of Fig. 2. Fig. 4 is a projecting apparatus for delineating the temperature-pressure variations of a gas. Fig. 5 is an indicator for automatically recording temperature-pressure variations. Fig..6 shows a projecting apparatus for delineating temperature-entropy variations from the delineation of temperature-volume variations. Fig. 7 shows a projecting apparatus for delineating temperature-entropy variations from the delineation of pressurevolume variations and embodying the prin- 'ciples of the projecting apparatus shown in Fig. 8 shows a similar projecting apparatus slightly modified in form. S) shows another modification of the projecting apparatus of Fig. 7. Fig. 10 shows a projecting apparatus for delineating temperature-entropy variations from the delineation of temperature-pressure variations of a gas. Figs. 11, 12 and 13 show modified forms of projecting apparatus for delineating the temperature-entropy variations of a gas from the pressure-volume variations thereof and embodying the principles of the projecting apparatus shown in Figs. 4 and 10. Figs. 14, 15 and 16 show forms of indicators for directly and automatically re-Y cording the. teinperature-entropy variations of a gas and constructed respectively upon theiprinciples of the projectors shown in L* ins. 7, 8 and i). Figs. 17, 18 and -19 show similar indicators constructed according to the principles embodied in the projecting devices of Figs. 11, 13 and 19., respectively. Figs. 21 and 2() show respectively a plan and elevation of a scale adjusting arm for an'indicator of the type described. Figs. 22 and Q3 are illustrative diagrams. Fi s. 24 and 25 lshow further inoditications o? an indi! eating device and projecting apparatus ref spectivcly for delineating temperature-entropy variations of a gas. Fig. 26 shows a. modified form of indicator wherein relative movement of the recording medium and the marker is obtained partly through optical means; and Fig. 27 shows va form of volumecutropy indicator, which combines the entropy motion as utilized in Fig. 15 with the volume motion instead of the derived ternpcrature motion. Fig. 28 shows a modified form of optical apparatus, utilizing electric mcasiu'ements of temperature variations and embodying the principles of proiecti" paratus shown in Fig. 6.

Referring to Fig. 1, I have there shown the essential features of a rojecting or tracingr apparatus whereby ti'i marker from the work or pressure-volume 'ere may be pro` hiced b v means of a. .continuously 'moving diagram 1 of an ordinary indicator card (here shown as drawn with reference to the rectangular pressure; and OV representing volume) a second diagram 2 (drawn with reference t0 the rectangular coordinates 'OT representing temperature, and OV, re resenting volume) showing the correspon 'ng variations in teinperature'and volume of the same-gas. The curve or diagram 1 shows'y the variations in the conditions of-agaseousbody, such as the charge in the cylinder of a. gas engine,v represented inthe pressure-volume or PV plane, and the Adiagram 2'the conditions of cordinate OP representing` the same gaseous body represented in the tempera turc-volume or TVplane. Since the principles involved in such apparatus enter into the construction of various-modified and amplified apparatus hereinafter described, reference will be made to the factors governingr its operation.

From the laws of perfect gases the pressure of a gas equals a constant quantity mulvti plied by the ratio of the temperature to the volume, this relatonbeing expressed by the equation In other words in the TV vplane all points representing the same pressure possess a constant ratio between the temperature and the volume.Y The representation of bem`.

12'5 represented of a gas having the constant pressure b by the line Ob and that having the constant pressure c by the line Oc. Furthermore at any txedvolume o the gas will Ldertll'e pressure a, band c the corresponding tlpellaturet, t? and t?, respectively, Havingreferencestill to the diagrams shown in` E1g. -l ;ff.f a= marker is moved horizontally ori parallel with the axis OV in accordance with-@blume variations represented by the .diagramidgit will delineate suchfvoluine variatibntiu ythe-TV plane. But iityvilnl also, be evident from theLabove stated ,relations between' tlhe'temperaturq-volume and pres- .s' ure,ftbt, if the marker :ciscausedgtoinove thatiiitsisgadapted to impart thereto a move` I mbntg'dirtxtly proportionate; to the volume variatonsish'own b y fthe curve 1i f'fhele iS farther. fprovaded. a temperaturey directing armf4 andfapressure directing arm .5. lThe nrmlfiiS-arranged always to vpassthrough .the kgiim-O,land'is*so connected to the marken gz: the volume director and-,the pressureiireetor 5 that it isadapted Ato impartito Alle; markenfa movement at right @inglatefits volume directed movement and paralleli to.the axis-10T, such movement g bekngrdompounded of-` the separate movements iofg-,the'tvolume'land pressure directors 3 and nsmdiipmportional .to the productIof the ozblumeind' the pressure: variations i shown 'by tha Ieurvel. ,To this end the temperature ,tlireeting`:anni 4` mayybe provided withv an 4Q felongatedfslot b'y means of which' the 'arm ida-ptedto slide-upon the tixedpin 7 at :the irlgin 1O and also uponapin 8, the lat- ,te'r-tixedly secured to the vertically movable 1.pressure:director r The marker :l: is sed. -cure1y ti:ed;to the. temperature director 4, .but-receives vertical guidance by passing rthroughiaa longitudinalslot 9 in the volume director` 3, so that, as the latter reproduces @variations in vollune by moving' along the vblumev axis OV, 4the temperature arm 4 swings about the origin to successively difl|erent ';positions and (disregarding move- ,linento :the prcssurearm 5) the marker' aciSraisedjox lowered as the-case may be.

-: 6The,pressure directing arm 5 is adapted to lslide vertically through a fixed guide 10. As thepressure arm 5 is raised er lowered to reproduce pressure-variat-ions, the pin 8 slidthe slot tilswings the temperature arm 3" about .its axis-which (disregardingmovement of thevolumo .arm raises or lowers a rod 1`1, the latter slidable through a sleeve 12 carried by the pressure arm so that as a and: volunrie represented in the curvel, the,

suitable tracing point` which, for example; may be positioned at Yvon the volume arm 3, is moved along, the outline'of the dia-g'A gram l the volume arm and the pressure arm combine to impart to the marking point a: notionly' the horizontal movement designating variations in volume, 'but also a -compound verticalmovement proportioned I to the product ofl pressure and volume and.. '4* correctly representing in the TV plane `corresponding variations in the temperature o f" the gas. A

To utilize the described projector' forV drawing a temperature-volume curve,y froml 4the indicatorcard diagram of a gas'eng'ine, 80

for' example, the clearance of the engine should be rst determined and expressed liIVL per cent. of th'e pistor'ldisplacement. 1 From this, together with `rth'e'y atmospheric -pressure and the scale of the indicator Spring, the zero pressure'line, orthe axis OP, and thepzero. volume line, orthe axis OV, can be then determined andv drawn. The project# ing apparatus can then 'befDplied with the, pivot point, 7 at any convenient 'point-'lon 90 the ressure axis OP, and the guide 1-,0l vtixel pre era-bly between theindicator card,` and the pressure axis. The pin-1S 'should'theh be adjusted to such position onthepres'surel arm thatf-the distance from the ypin 8 to the 95 V axis in the-,TV planef is equal to the distance froinithe tracery totheVaXis in"tli e PV plane. By guiding.,r` th'e`tr'acng i'fo'ir'jit y carefully around the card, themarking'`A point will draw the `temperature-volume curve. The pin8 may be adjusted tofzdifferent positions along the pressure arm to 4 admit ofany desired distance between; the origins of the PV and TV planes, suchy a'djustinent being determined by the size of the diagrams. By fixing the guidelO ati-.different positions along the axis-OV any de sired ratio between the temperature` and pressure scales-may be secured.

lt will be obvious that the described device (like the other projecting devices hereinafter described) is reversible and that any delineation of temperature-volume varia'- tions may bO-projectcd into thePVpl-ane lo show `corresponding pressureivolume varia-115 tions by using w as the tracing point and fyas the marker. This capacity,` for example, may he utili/,cd to draw a series of 'isothermal lines `in the PV plane by guiding' the point alon a straight edge` placed parallel to-the axis` V, whereupon the Ypoint y, if used as a marker, will draw'a. rectangular hyperbola expressing thev relation [roza constant. I f Y It will beu1ide1sto0d`thal thc apparatusis 125 herein illustrated in` semi-diagramniatie forni in order'lhgitfits essential parts may noty be. obscuredv by, the',` details v of v.mechanical (l construction and that its principles opperation may be more clearly depicted. ijhe embodiment of this, as well as other devices hereinafter referred to, in the form of tinished and complete mechanical instruments, will be readilv understood bv those skilled in the art.

By embodyingr theV rinciples aouve described in an engine indicator, the temperature-voluine curve. can be recorded directlyY and automatically' upon the indicator card.

`latter will move in accordance with variations of volume. L InF ig. 2 such an indica tor is shown, the-same being provided with the usual indicator cylinder 13 containing the piston`14, working against the spring 15. The piston rod 16 constitutesthe p'rcs- ."snre director and has connection .to vthe temperaturev directing member or slide rod 117 by means ofl'a pivoted sleeve 18. AThis connection should be1 adjustable, 'as slown,

so that at atmospheric pressure the distance between the'center of the pivot-ed sleeve 18 and the horizontal line through the center of pivot 24 canxbe'lmade equal to atmospheric pressure expressed in 'terms of the `-peratue director l'lis pivotallv'secured to the marker-carrying block I1f) the latter bcing slidable in a vvertical slot formed in the volume director 20.

The volume directing arm zu is mounten 'upon the ca rrier2 1,adapted to have a sliding .movement f'onljtlie guide rods 22 (see Fig. 3); The. carrier 2 1 is attached by the Cord 23- through v any usual reducing meehanismtnot shown) 'to the'ehgine cross head, so that'V the marker 'is 'given a horizontal lndvernent f roportionate to 'variation in 'volume of tic'fcylinder charge. The oppo- .'site c'nd' of the directing' arm 1T passes througha second sleeve 24, pivotally secured tothe fixed' post 25 so 'that there is fixed a pivotal point corresponding to the origin O in Fig'. V1. The carrier 21 also sustains the rotatable indicatordrum 26 of any usual construction. .lhe-drum haswonnd 'thereon the cord 27. thoopposlteend being secured toany. .i tixed point, such as the post 25, so that', astlic carrier is moi-ed hack and forth on theguide rods, the drum, with` the card securedthereto, is not only carried along with the carrier-but. is also turned "beneath thc marlt'er, presenting thereto sin-- t-essive. portionS'O t le Card Surface. The indicator card therefore has `the saine. relation relatively to thennarlienasin lhe case of lheiprotec'ting apparatus shown in Fig. l. 'lhe usual spring within the indicator drum serves-us a return sprrngtendrop'ortionateto variations in pres- 4 ing to wind up the drum so that on the return movement of the engine piston the carrier and the volume arm are moved reversely. It will be evident that a relative movement' of the kind described is all that is necessary between the card and the markerand that the latter might be stationary and the card movable, or the card might .'be a fixed plane surface and all movement performed by the marker, or any :other desired .arrangement of the working parts had to secure the object stated.

In the ordinary pressure-volume in clica-VV tor the line of zero volumevcan be estimated from the clearance and applied tothe card. after the latter has been taken. In thefdescribed indicator, however, the pivotal axis of the sleeve 24 should occupy a definite' re` lation to the line of zero volur'i'e, sojthat the l indicator should be initially adjusted -lto preserve the desired relation 1n this respect.

To this end adjustment is provided on the described form of indicator so that therdistancc of the volume director from theorigin Y at the .beginning of a stroke shall have'the same relation to the length ofthe strokezsls has thel clearance space of theengine or compressor to its in an adjustab e scale 28v is Securedto the indicator parallel with the movementof the volume director, such scale having marked thereon between graduation O and 100 a selected arbitrary length of stroke for the volume director. The reducing mechanism is then adjusted so that the movement of the volume director will be ual the select/ed Stroke length.

iston displacement.; Here- Y At the left o the zero mark on A the scale there are provided gradua'tionsl ex# Y pressing percentageof the selected stroke length. If the clearance of the engine, for example, is 32% of the piston displacement, the aduation representing 32% will jbe positioned beneath the pointer 29 which is attached vertically below the center of the pivoted sleeve 24 and represent-s the point of zero volume. The scale is slidably mounted on brackets 30 provided with clamping screws so that it can be adjusted as rex quired. Following this,lthe cord 23'is then'.

so adjusted that, at the beginning of the piston stroke, the pointer 31 onthe carrier .21 stands at the zero niark. This provides such a condition that the conditions of the diagram in Fig. 1 are reproduced and the distance of the volume director to theorigin is always proportionate to the true volume.

The same general principles as are cmployed in the above describedapparat-ns for ilelinealingr the. temperatnre-volume variations of the. `eas may he utilr/.ed for drawing the tempemture-pressure variations of a gas lu l"ig\ 1 and 5 l have shown devices for projecting and automatically recordingr ricspe'clively thel changing conditions of a gas ing pressure variations instead ot with reference to volume and temperature variations as in the apparatus o Figs. 1 and 2.

Beferrino to Fig. 4, the tracing point y, which is adapted to follow a curve drawn with reference to the axes OV and OP, is carried by the pressure director 33 and also has attachment to the volume director 34 by means ofjtlie rigidly connected rod 35 and the sleeve 36. The same connections are herein afforded between the tracing point g/ and the marker a: as in tlie case of the apparatus shown in Fig. 1, except that the connections are reversed with reference vtothe pressure and volume directors so that the marker is moved parallel to the axis OP in direct proportion to the movement of the pressure director in proportion to the product of the movement of the volume and pressure directors. The marker, therefore` will trace with reference to the axes OP and OT a curve of varying temperature and pressure if the tracing point y is caused to follow a curve of varyand volume. p ln Figi. 5 is'shovvn an automatically recording ciples of the projectorsho'wn in Fig. 4, so that the marker moves vertically in direct proportion to'the varying pressure of. the cylinder charge, while it moves horizontally in pro ortion to the product of the pressurecausedp movement and the volume-cam'sed-` movement. The construction of this indicator will beV readily' apparent from: the

drawings: in connection with the description of tlie previous apparatus. In thev indicator of Fig. 5 the recording surface 37, instead of being carried vby a rotatable drum, vis fixed, and the marker moves over the plane surface of a recording sheetthereon. The

volume-director 38 is mounted to slide upon a guide rod 39, being moved in one direction' by'tli'e cord 40 connected to a reducing mechanism, and in the opposite direction by the cord 41 connected to a barrel 42 containing a suitable returnspring. The curve tracei upon the indicator card 37 will represent changes in pressure referred to changes'in temperature o the gas in the engine cylinder. The initial adjustment ofthe parts may be carried out in substantially the same fashion and by "the same means as those shown in connection with the indicator of Fig. 2.

Referring now to Fig. 6, I have there shownan apparatus whereby from a temperature-volume curve suoli is-maybeV produced either by the projector shown in Fig. 1 or the indicator shown in Fig. 2there maybc drawn` by a continuously moving'marker, the curve representing the corresponding tempeinture-entropy variations of the gas. 'l`lie entropy of a perfect gas (which may lfeexprhcssed for convenience by may be and parallel to the axis OT indicator constructed upon the prinexpressed in terms of the temperature and volume thus: 'u

(l) o O log. T-l- (c- 1) logi. vl-constantv or it may be expressed in terms of Atlm fpm, perature and pressure.

(2) 15 OC log. 'Il-7S? or ine terms of the pressure and voluin'e,thusc (3) 45 o( log. p-l-c log.

k being a constant quantity degendenbo'n the particular Y gas under consi eration1 Hand equal to the specific heat at constantpre's- 4sure divided by the specific heatfatcstaiit volume, z'. c.

i gli l Cv-i I In Fig. 6 I. have there shown an apparatus where-the marker w is caused totmovfehonizontally, or parallel to the entropyaxi's! Q,

proportional to vthe value 'of entropyrrep-- resented by the first equation fgive'n ahogo. That is to say, to the marker.there:i's;3not only imparted a movement paralleletoftle axis OT proportionate-s to. itempeate changes, but also a movement parallelitostlxb O4 which is proportionatertoftlrediigrithm of the `temperature f vaiationsalpl-irs (kl) times the logarithii-jfetheafvolinhp l variations.A ',correctlyreproduces the entropy'variations ofthe-gas. To this end the maileili'mps mounted onan arm 43 wlichsadpteditp -slide horizontally through thefsleeve The latter movement; ilierefor,

the tracing point y. The sleaveiirs 6 secured tothe temperature director 4 variations of temperaturerepresented lybthe 'temperature-volume curve .andwixnparts-fm like vertical movementidirectlyzft:

log. p4-'constnnfffmarker As the tracing'po'ihtyiistnoved horizontallyit imparts a like' movemeiitrto the volume director 47 by meansofthe'sleeve connection 48 between the latter 'andiiie temperature director, 46. The rmovementoofthe vol-imc director, ho\vever,is transmitted to the niarker a: through therinteipositinbf a logarithmic director so that tlief horizontal displacement of the marker-Educ to Fthefdisplacement of the volume directoris equaliito log. o, At the sameV time'thevvertiealndisplacement of the temperature direetiorifiri'- parts. to the marker a horizon-tal' displacement equal to log. T which is addedtolthe volume-caused this end the sleeve 48 carries a pin 49-jxvhi-chherein receives guidance from' ar directing movement ofLthemarker.: To

slot 50 formed in some fixed part of the -apso that; as the volume director para-tus,

it is galso caused to ni'ovfv moves laterally, vertically in confomianc'eto the sha slot. The. slot `herein constitutes tA e --logae of thefi fad rithmic director referred to, being shaped with reference to the axis OV in conformity to the expression (k-1) log. o. That is to say, as the volume director moves laterally to represent change from one volume to another, it will also be movedrvertically from a position representing (lc1) times the logarithm of the rst volume to a positionv representing i the second' vo ume. -To transmitthe movement of the volume director 47 to the marker the former is caused to move the sliding carrier 51 along the guide rod 52, the carrier having a depending arm 53 provided with -a slot 54. The vertical movement of the volume director 47,' however, as restricted by thecguiding slot 50, is first converted into a horizontal movement of the carrier 51 by the following means: Vorlring within the slot 54 on the carrier arm 53, and also within a tixed'slot 55 arranged at an angle of to the axis OV, is a guiding pin 56vcarried by a sleeve 57 through which the volume director-has a horizontal sliding movement. As the volume director 47 moves vertically, the sleeve moves vertically, but also moves horizontally by an equal amount vdue to the guidance of the slot/55. Horizontal dislacement of the sleeve 57 is communicated y the pin 56 to' th/e' carrier 51, so that the latter lreceives' ahorizontal displacement equal ,to (ls-1) log. v.' The carrier 51 is provided with au arm 57 having connection to the marker carrying arm-43, so that. the latter also receives a displacement equal to (Ic-1) log. o.Y To communicate an additional horizontal displacement to the marker equal tolog. T, the connection between the marker carrier and the carrier is provided in the form of a pin 58 xedly secured to the varm 43 but working in a slot 59, the latter so shaped with reference to the temperature axis that it follows log. T and guides the pin and marker carrier 43 horizontally in accordance with log. T. 'lhat is to say, the slot conforms to a logarithmic curve such that each vertical movement of the tempcrature director is accompanied-by a horizontal movement of the a'rm 43 which displaccs it by an amount (,disregarding its volumecaused-movement) equal to log, '1. 1t will therefore be seen that, as the tracing point y i is caused to followrthe outline of any teinother words,

peraturefvolume curve, the marker will move vertically I according to temperature variations, and horizontallyy according lo tho logarithm of the tempi-.rature plus (1. l; times the logarithm of the volume. or, in according to, changes in entropy.

It will 'be evident that Athe apparaius f A shown in Fig. 6 maybe revcrselyuised to draw' the temperature-volumecurve from the temperatureentropy curve by placing k-1) times the logarithm of/l the tracing point/at :v and the marker at y; also that the /ni'arker at y may be made to draw a series'of adiabatic curves in the TV plane by U/uiding the tracer at a: alonga' straight/coge placed arallel with 'the-airis@ O4 twill also be evident that the requisite rel tive movement between the marker and /the recording surface may be obtained by combinations of movements other than-the precise ones shown in Fig. 6. For example, the marking point a: may be given vertical or temperature dis lacement, only, and the recording surface t e horizontal or .entro yv displacement; or the marker may have tie: horizontal displacement log. Tand .the recording surface the dis lacement (lc-1) log. v,- or thefmarker 4tiie horizontal displacement (lc-1)" log. i; and the recordingsurfaoe log. T. These minor variations in' Aform are all within the spirit of my invention and. will be understoodas .tov the de-A vices hereinafter described without neces-- sity of further mention.' The combination of the principles underwhich the project-I ing apparatus shown in Fig. G and 'that shown in Fig. 1 are constructedniay be usefully employedvto project a pressure-VOL' nine curve such as is contained on :in ordinary indicator card from the pressure-volunie plane into `the temperature.entropy..

volume curve located with reference to the axes OP and OV, the various )arts of the apparatus being designated by t e saine numerals as the corresporidino parts in the devices of Figs. l and G. In t'his case the-pressure director 5 is connected to a temperature arm 4 and volume director 3-47 in substantially the same manner as is the case of the projecting apparatus in Fig.'1, so that the traveling sleeve member or temperature follower 60 is caused to move vertically in accordance with temperatureqariations and horizontally in accordance with volume variations. lhe teniperat ure variation movement. of the follower 60 is then coinmunie-ated to the marker a: by connections which are substantially the same as those shown in Fig. G. 'lhc inovei'nent of the vorlnine director l--t is also communicated to the marker .r by connections which arc' substantially the same as those in the apparatus of Fig. (i, that Starting with thc morena-nt of the tracing point y followingr variations in pressure and volume. ilu: marker :c is caused tofollow and delineate variations in temperature-and entropy.

ln accordance with the third expression for entropy, the latter may be regarded as curve with relation tothe i .arm and working in a slot i marker equal-to c g- U .varying in accordance with the logarithm of the pressure lus k times the logarithm of the volume. hev same result, therefore, vmay be obtained'as in the apparatus of Fig.

- 5 7 by impart-ing to the marker a horizontal displacement roportional to the logarithm of 'the vertica displacement of the pressure director 5 and adding to that afurther horizontal displacementY equivalent to k times the logarithm `of -thehorizontal displace4 Ament `of the, volume director 3-47. This accomplished. by causing pressure movement ofi. the tracer y transmitted through the double-.sleeve and the sliding arm :the 'pin 63, the latter carried by the said` 64 presented by the movable carrier 65. 'The slot 64 is shaped to conform to log. p so that vertical movements of the tracer y are converte into horizontal movements equivalent' to log. p and theseare to'I be tically slidable t marker arm 68.

An.. additional communicated to the rough the eeve -67 onn the horizontal movement 'Y is marker .l armf an through the horizontal movement of the carrier 65. To pro duce this movement the volume directoifz is rovidedwithr a pin 69 constrained' to move lin :the slot- 70, thel'atter shaped in accord- 'ance `.with the-'variations of k lo v. The

Yare

-'F1g.7..' '1`l1e movement of themarker therefore in a horizontal direction records variations in Aentropy justas'in the' apparatus'of Fig. .7, although utilizing different A'movements of ,the intermediate linkages." 5 Similar projections ofthe temperature. entropy .variations of a gas may be secured by means of movements conforming to the second expressionfor entropy, that is cc log.T --(-N k.) log. p+constant i i -H'ere the tracer havingl horizontal sliding movement on the arm'72 which latter arm, however, causes the Amovementof the pressure-director 5. The marker carrying arm 43, moving vertically as it does, through Ylar to those in.Fi 1 and in the a paratus alsofof Figs. 7- an 8; carries a pin. t3 which works in a slot 59 shaped to conform to log. T; so that the afrm 43 and with it the marker m ,have a ihorizontal movement equal to log. -The carrier is also provided with direct the vertical or 6l, Y 62 carried thereby, to.

transmitted to the up right arm 66 secured to the sliding arm 62'at' any convenient ppint as the plin 63 and vel:-` f25 S vertical-movement of thepin (S9-1n the'slotV` 70is communicated to the carrier as a horizontal movement by connections whic substantallythe same as those shown'in "r (1001' at'y, and rsuch apparatus is yshown in Fig. 9 -is secured to lthe sleeve 71 rigidly carried: 'y.the'.volume arm 3, Abut connections simiing means, such as the slot 74, which receives a pin75 on the arm 72 and partakes'ofithe Avertical pressure-caused movement ofvthe 'tracer y. This slot is shaped to conformto the expression (#1) Yf-Lf log. p so lthat the carrier and the marker lx-.ivetziii Vadditional movement equal to '.373

A- Si?) 16g-13,'

or,in other words, a total movementcorres ponding to the entropy ifariationsaff #X7- 80 pressed in..terms of the pressure vandi-temperature. f I n z It will-be seen that .in each of. thegthree projectingdevices shown in Figs.--7r.,.S,aIid-,-9, Y

like that shown in F ig. I1, there isprovided *a temperature follower' (l0 which v'1s-directed to mov'e in accordance to variatiousgofipressure and volume, and that suchmotionys communicate Ito an appropriate.marker.; It- 'ivillwllso be 4 4 A, munieated t it a movementat rightaugles' 'to its first# entioned fmovementgi whiolh is compounded fof the movements. of the, tenuy perature follower and volume diieetor .in one casegthe pressure director and \fo,lLln1,:95 director iu another case, and the..tempera-V ture follower and temperature directorgina thirdcase, the movements in each:instance,v however, being appropriately. converted,i y suitable-logarithmic directors, to ,impart e210() resultant 'movement to the follower propontionatejto'entropy .variations of thegaa. L,

.ltwill be evident that'in any.' offthgrpro- Lectors described a marker-might bocariried y the temperature follower mnd-caused to 4trace the temperature-volume curve simultaneously with thcrtracing of the temperatureentropy curve by the marker w., i As in the case of the projectors previously described the projectors illustrated in Figsil 10 7, 8 and 9 maybe used rcrersely Aandail'diabatic curves may hc 'drawn Vinp'eitheri'fthe TV or PV )laura by.' placing the'juarkea; at

t icu adjusting it upon any point through which au adiabatic curve isgto. b e 11:5 drawn`and then constructing thccurveby guidingv the' point n@ along-a straight edgeparallel to the axis 1 .l

In Fig. l0 I have shown a propo-ting apparatus similar to that shown inFig.A pbut.- serving to project the temperaturefpressure variations of a gas `into the temperatureentropy' lane.I The tracing point yis earried by t ie arm' which is caused totransform the horizontal prcssure-causeddisy placement into an entropy displacement ot the 'marker w. The arm passes through4 a. 4sleeve VIZ carrying a pin -78 guided` by,J the slot 79, which transforms the horizontal dislacement of the arm 76 into a vertical displacement of the pin 78 and arm 79 carrying the pin proportionate to (Referring to Big. fr, the volume director '1844:is1moved laterally.. by a suitable connectio'n to the engine'pis't'omthe conneces` tion'alsof'extending tothe block 86sliding in the vertical fixed gnidew ay 87. From the able return device consisting of a spring contained within the barrel SS. Variations iii volnnie in the engine cylinder are accom- (Ic-i) 10 "#ki log. p. pained by a horizontal movement of the di rector Si and :i vertical niovenient of the This is communicated to the carrier 80 as block 86.' The block carries a pin S8* slid- Y to horizontal movement by Ameans similar to ing in the logarithmic slot Si), the latter bem those heretofore described. T o this horiing presented by :i carrier 90, slidablehorif 75 zontal displacement of the carrier is adde zoiitally in lixed guides 91.` The opposite a horizontal displacement due to the pin 81 end of the carrier also presents a logarithmic carried by the marker 82 and working in a directing,r slot. 92, which guides the pin 93 slet SR presented bythe carrier and shaped secured to the marker arm, so that a's the Y 15 to 'contorni to log T., The projecting appatemperature -following sleeve 94 is raised 0r 80 ratus of. lfig. l() can be combined with the lowered with the variations of temperature apparatus ot' Fig. 4 for proiecting pressure- (similarly to the movement of the block 1E)i volume variations into temperature-entropy in Fig. 2) the marker and its arm are also variations. Three oi'ins'of such devices are moved horizont-.illy iii accordance with vashown in. Figs. 11, 12 and 13, these being' riations in entropy as given by the cxpresg5 constructed according to the three diierent sion expressions ot entropy previously given. 10g 'f i (]c. 1) 10g` 1v. .These devices shown in Figs. 11, 12 and 13,

diti'er from the temperature-entropy pro- The'holder 9:', with the indicator card is 2.3 jectors shown in Figs. and 9 in that. herein held tixcd, the niarker'heing caused 90 the temperature follower 60, as in the appato traverse its plane surface. ratos of Fig, 4, moves in accordance with lt will be noticed that an instrument like temperatorc-pressnre variations instead (if that shown in Fig. 14: or delineating the teinpemtnrc-rolunie variations, temperature and entropy variations is coni- :io In Fig. 11 the marker is displaced parallel vpounded of several primary following meni- 95 i with the entropy axis in accordance with the bers which themselves execute movements -logai-ithin of the pressure plus l.: times the proportional toall four properties of the logai'itlnn of the volume. 'lhe construction It 1S POSSlble, therefore, by applymg of the linkages and connections which eonllnnkcl t0 tllc dlfelent following members .ei-t the iiiovenientof the pressure and vol- 0 th .lnd'lCiltOl' 0f Fig. 14 t0 Secure imylOO inne directors into an entropy movement desired curve. For example, there may be' will he apparent from the drawings in conproduced, if desired, simultaneously, Aan 'nee-tion with the description 'which has von thesnme' record sheet, with the' curve 1 'niwiidy been 'given l A ot temperature-entropy variations, also 40 In Fig. 12 the horizont-.ii movement or the curves representing the pressure-entropy va- 105 marker is secured by 'imparting thereto a viations, volume-entropy variat10n's,tcm displacement. equal to peinture-volume variations, temperature- (k 1) pressure, and even the pressiirevolun1e va -E riations. Temperature-volume variations .i5 may he recorded by a marker located at :c 11o tiIiiCS the lgllitllm Of thc plSStlY (llSpl .lCC- \lu1nccnt,r0py variations may be record@ inent and a second displacement in the Opby a mai-ker located at e Yon the double.'

iosite direction equivalent, to the. logarithm sleew represented by dotted lines and of the temperature displacement. i guided on rods 0r|inenibers rigidly 'securcd .-.n' In Fig. 13 the marker w is displaced parl togthc pins 93`and 8SK respectively, such rods iis alle-tto the entropy axis by aiianiouiit equal i hcig dianrgimmatica y' represen by to the logarithm of the teinperatni' plus l dotted lines to avoid confusion in the dra'W- (f1 times the logarithm of the minnie. ing. The pressurecntropy variations 'may As in the ease ofthe temperatore-voluine he recorded by a marker loeatedla'it ai and 5r, projector' and indicator the teinperaturccarried by the double sleeve shoijnin dotted 120 entropy projectois shown in Figs. 7, 8 and 9 linosgsuch sleeve being 'guidd-lon'frigidlds present a readil y available means; or coii-v or nelnbers connected tp the'lpin93 and the i 'strncting-indicators adapted to`iec0rd`auto indicator .piston rodi;'resplectiivel4 Q 'i inaticallyj-the y temperatoreyentropy varia- Iii..-I"ig. A16 ther-'eis ,s own'an 1n oo g'tion's of the lgaseoiis'charge in the engine cy wherein the4V movement of the mark 125 allcl with the entr' `py a'xis'is caused-f4 rithmic pressure, and vlogaritln'nicpcaused movements. fz is converted-into an'entro 'the marker-d: by` means oft 96 which, through the guide slot 97, controls the horizontal movement of' the marker. The carrier to presents the directing slot 98 to a pin 99 carried by the arm 100, the latter attached to the piston of the indicator. The directingr slot 9S being shaped according to log. 7i, the horizontal movement of the carrier is proportionate to log. p. In this indicator the required relative movement between the marker and the record sheet is all'ected by also moving the card holder 101 proportionately to log. o, and in a direction eppcsite to the required movement of the marker or equivalent to' log o. IIor this purpose the holder 101 carries an extension 10:2 which presents the guiding slot 103 in which works the pin 101 carried by a block movable vertically with the horizontal movement of the volume director. This secures a relative movement between the marker and the recording sheetwhich is equal to the entropy variations expressed by log. p-l-c log. o.

'lhe third variety of projector shown in Fig. 9 can also be embodied in the form of an indicator, such embodiment being shown in Fig. 16. Herein the vertical movement of. the temperature following block 105 is transformed into a horizontal movement of the marker by means of the pin 106 on the sliding arm 107 which pin engages a directing slot; (log. T) on the carrier 108. The carrier also presents a slot shaped accordingto Y which 'receives a pin 109 carried by the pistonstem 110, so that the piston movement is also transformed into a horizontal movement of the marker, the two n'iovements effecting a displacement equal to or proper-- tional to the entropy change.

.Inlfigs 17. 1S and 19 there are shown indieators developed from the projecting appai-alusshown re peetively in Figs. 11, 13 and 12. sive member ll'l ir: moved verticallyY under the direction of a horizmitally moved pres .sure arm 112 and a vertically moved volume director lli. the latter comprising a block slidably mounted in the e'ilidewayIM and eenneeted to the cross head or piston hy the connector- 115. Appropriate horizontal movement is `given the marker :u to conform to entropy variations by a combined movement ol the earrier 1.11") and -tlie card holder 117. 'The vl'ormer is provided with a vertical slot 11S whit h guides the marker carrying lil-eelt 110. movement heiner imparted thereto proportional to log. ,o through mechanism wheh is similar lo that previously described and is controlled by the piston actuated pin 120 worlting in the director slot 121. On the ln Fig. 17 the temperature respon-V ing sleeve 124 in the slot 125 (log. T) and through the further guidance'of the holder 111 by means of the slot 126 shaped to eon form to v (Ic-1) log. o.

Thevertical movement of the temperature follower 111 moves the sleeve 124 vertically and therefore laterally through the guidance of the slot 125.' Vertical movement of the volume responsive member 113 and the oonnected pin-122 moves the holder laterally under the. direction of the slot 126. The relative displacement between the marker and the card isztherefore proportional to the entropy variations.

Referring to'Fi'g. 19, the temperature follower is moved laterally directly from the pressure actuated piston rod 127, its vertical movement being proportionate to temperature variations. Its vertical or temperature responsive movement is communicated to the marker :1; which, through its engagement with the logarithn'lie slot 12S (10g. T)

moves the marker-carrying arm 129 and the marker horizontally to producen displacement in proportion to the logarithm of the temperature. At the same time, through connections similar to those previously described, the carrier 130, which supports the arm in which isformed the slot 12B, is moved in the opposite direction by nieans of the engagement of the pin 131 in the slot 132, the said pin being moved in response to the. pressure-actuated movement. of the stem 127. The slot. 132 being shaped to conform to the expression the. resultant horizontal movement of' the marker over the face of the fixed card holder 133 is proportionate to variations in entropy.

In Figs. 20 and 21 I have shown an attachment for readily varying the stroke or movement .of the volumedirector so as to bring itinto agreement with the scale 28 deseribed in connection with Fig. i?. It may happen that, througlwear in the brass s, or for other reasons, the actual engine. stroke varies somewhat from the dtsigned stroke. Under such circumstances, if the volume director starts at the scale marltOonthe scale iigFig. 2, it will then overrun or fall short of the `scale marl; 100 by a small amount. To avoid this there ma be attached to the indicator au adjusting arm 134 pivoted at 135, This arm has a carrier. 13G slidably mounted thereon and moved by the cross head attach ment 137. Motion is transmitted from the carrier 13G to the volume director by means Y of a block 138 pivoted on the carrier and slidable laterally in the slotted member 139, the latter projecting from the volume direc toi-. The apparent stroke, as measured by the movement of the carrier 13G on the arm 134, is thereby converted into the more or less reduced movement-of the volume director according to the angular position of the arm. The latter is adjustable upon the .segment 140 to which it may be secured in any desired position b v a vclamping screw 141. By this means the relation of the volume director to the other fixed parts of ,the indicator eanalways be kept what it should be. i v

In the projectors and indicators previously described the marker is caused to follow in one direction the movement of a temperature follower, which latter has` a l movement compounded ofthe movements of the pressure and volume directors. possible, however, to convert the movements of the pressure and volume directors directly into a temperature-entropy movement of the marker without the interpcsition of the temperature-follower. The construction of the apparatus will be understood from the followingronsiderations.

If there are represented both in the pressure-volume plane and the temperature-entropy plane a constant pressure and a eon- -stant volume curve, any condition defined by the intersection a (see Figs. 22 and 23) of a given constant pressure curve and a given constant volume curve in the pressure-volattire-entropy plane, ara moved parallel to stant volume Curves are of the same contour so that if tvvo slots, so shaped as to represent respectively a constant pressure rin-ve and a constant volume curve in the temperthe entro'py axis they may be ma'le to assume successively the positions-,of all constant pressure and constant volume curves.

If the constant pressure slot can lic moved along?r the entroi'iy axis to correspond to movements of the pressure director alongr the pressure axis, and if the constant volume slot can be moved along the entropy axis to correspond to the. movementsof the. volume director along theY volume axis, then the intersection of the constant pressure and con IK. Cv log. 'l`-(/.:-l1) Cv log. p-t-constant on dividing,r by C- we obtain 0 log. T-t- (c- 1) log. 'v+constant 15 OC K log. T-(k-l) log. p+constant.

Therefore at constant temperature if the volume direct-or in the fr0-plane moves from position r, to position 'u2 the volume director must'. move parallel to the entropy axis from position (lc-1) log. o, to (7c-1) leg r2; that is, while the position of the volume director with reference to the volume scale inthe. p11-plane is'always proportional to the volume of the gas the position of the, volume director with reference to the location of the unit volume line on the entropy scale in the T4` -plane is always proportional to (.--1) times the logarithm of the volume of the gas, and similarly while the position of the, pressure 'directoirelatively to the pressure scale in the -pv-plane is pro: portional to the pressure of the gas the position of the pressure director' relatively to the location of the. unit pressure linel on entropy scale is always proportional to -(x-1) times the. logaritlnn of the pressure of the gas.

The proposed movement of the. constant pressure and constantvolume slots alouflr the entropy axis being aong au isothermal line, it; only remains to impart a movement to the constant volume slot. proportional to the expression (k-l) logl lf aud to the constant pressure slot a movement proportional to the. expression (/s-ll log. L

ln Fig, 25, there is shown a projecting' appa rtus based upon these, principles. 'Vlhe marker a' is guided by two slots 142 and 14?. The former represents-the constant volume curve and the latter the constant pressure curve. For the former any arbitrary logarithmic curve may he selected, 

